viafb: Depends on X86

VIA UniChrome and Chrome9 GPUs only exist as Integrated Graphics
Processors in x86 chipsets.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

drivers/video/Kconfig

@@ -1505,7 +1505,7 @@ config FB_SIS_315
 
 config FB_VIA
        tristate "VIA UniChrome (Pro) and Chrome9 display support"
-       depends on FB && PCI
+       depends on FB && PCI && X86
        select FB_CFB_FILLRECT
        select FB_CFB_COPYAREA
        select FB_CFB_IMAGEBLIT